Endlessly varied loons in America (6)
I believe the answer is:
divers
'loons in america' is the definition.
'divers' can be an answer for 'loons' ('diver' can be a synonym of 'loon'). I'm not certain of the 'in america' bit.
'endlessly varied' is the wordplay.
'endlessly' means to remove the last letter.
'varied' becomes 'diverse' (I've seen this in another clue).
'diverse' with its last letter taken off is 'DIVERS'.
Can you help me to learn more?
(Other definitions for divers that I've seen before include "Several; snorkellers" , "ducklike birds" , "ducks" , "Some water-birds; assorted" , "Plungers" .)